Steam generator



June 13, 1961 H. voRKAuF 2,988,063

STEAM GENERATOR Filed Dec. 17, 1958 2 Sheets-Sheet 1 /l/E//vR/CH [/RKAUF A frown/y June 13, 1961 Filed Dec. 17, 1958 H. VORKAUF STEAM GENERATOR /Igl 2 Sheets-Sheet 2 F/gg Fig /0 lg Z9 Hema/CH /a/wm up United States Patent 2,988,063 STEAM GENERATOR Heinrich Vorkauf, Davoser Strasse 2b, Berlin-Schmargendorf, Germany Filed Dec. 17, 1958, Ser. No. 781,131 Claims priority, application Germany Dec. 27, 1957 11 Claims. (Cl. 122-336) This invention relates to a steam generator in which the gases flow in a horizontal combustion chamber in the longitudinal direction and in which, laterally adjacent to the combustion chamber, ues are arranged for combustion gases owing parallel to the gas current in the combustion chamber.

There exist steam generators with combustion chambers in which the flames are conducted horizontally in the longitudinal directon and in which the gasesat the rear end of the combustion chamber enter into gas ilues located laterally adjacent to the latter. the gases are also conducted horizontally and parallel to the longitudinal direction of the combustion chamber. Steam generators of the mentioned type are advantageous on account of their relatively low height. However, with the conventional steam generators great diculties are encountered when it is necessary -to clean or exchange the In these gas uesv ICC tudinal direction of the steam generator on the side of the gas fines opposite the combustion space whereas the upper collectors of the individual Igroups are located transverse to the gas ow and are connected to a main collector whichV is arranged above the wall between the combusion chamber and the adjacent gas ilues.

According to still another object of the invention, the tubular groups of the convection heating surface may be so constructed that they' extend through several of the gas ilues which are located one at the side of another one wherein a partition vertical to the tubular groups separates the gas flues from one another. However, it is also possible for each single gas ue to have its own complete tubular groups.

Further objects and details of the invention will ybe apparent from the description given hereinafter and the tubes of the convection heating surface which are not readily accessible.

The present invention aims to provide an improvement in the arrangement and formation of the heating surfaces of steam generators with horizontally conducted llames in the combustion chamber and horizontally conducted flow. The invention further aims to render the space above the collector of the mentioned groups of tubes readily accessible and especially -free from other tubular structures.

The invention further aims to arrange the steam separator drum above the combustion space wherein preferably the gas flues adjacent the combustion chamber are arranged on the one side thereof whereas the steam separator drum is also located in the longitudinal direction of the combustion chamber but on the opposite side. This structure offers the advantage that the combustion chamber and the heating surfaces in the gas ilues may be relatively high Within the above mentioned relatively low height of the steam generator.

The invention further aims to form the convection heating surfaces of groups of tubes which are all of a substantially equal structure so that the numbers of such groups need only be enlarged or reduced for boilers of varying outputs. Thereby even boilers with a super-heater arranged within the convection heating surface require only a minimum number of different types of tubular elements.

Another object of the invention is to form the mentioned groups of straight, vertical tubes or of tubes which are substantially straight in a projection at right angles to the cross-section of the gas flues. Such structure results not only in favorable conditions for the heat transfer, but also the tightening of the individual gas flues which are located adjacent one another, will be facilitated.

'I'he invention further aims to provide a structure wherein the lower distributors of the mentioned groups of tubes extend from a main distributor located in the longiaccompanying drawing illustrating an embodiment thereof by way of example.

In the drawing:

FIG. 1 is a vertical crosssection of a steam generator according to the invention along line 1-1 of FIG. 2.

. FIG. 2 is a horizontal cross-section of the boiler in a plane through the center of the burner opening, visible in FIG. 1.

FIGS. 3 and 4 are cross-sections according to the lines 3 3 and 4-4 respectively, of FIG. 2.

FIGS. 5 and 6 are side eleva-tion and rear view of a bankof a tubular group being part ofthe illustrated steam generator.

FIGS 7Vand 8 arejside elevation and rear View of a modiiiedbank of tubes. FIGS. 9 and 10 are side elevation and rear view of a bank of still another form of tubular elements.

lFIG. v'11 isa cross-section along line 11-11 of FIG. 2.

FIG. 12 is Ia side elevation and Y FIG. 13 is a top plan view of a portion of two modified tubular banks ywith a common connecting piece.

FIG. 14 illustrates the manner in which the econo mizer tubes 16 are supported.

FIG. 15 is a cross-section Valong line 15-15 of FIG. 14, and FIG. 16 is a modiiied portion of a steam generator with differently arranged return pipes.

Referring now to the drawing, a steam generator according to the invention is provided with an opening 1 for anoil burner (not shown) in its front wall 1. As indicated by the arrow a in FIG. 2, the ilame is conducted ,in 'a horizontal direction through the combustion cham ber 2. The front wall 1, outer side wall 5' and rear wall 6 are lined with radiantly heated tubes 3, 5 and 6, respectively, whereas the inner side Wall of the combustion chamber is formed by a series of tubes closely adjacent one another or the wall may be made of refractory material and lined by such tubes. The bottom 7 is not cooled in the illustrated example. In a boiler of this kind, a grate (not shown) may be arranged at the bottom so that the boiler can be heated with coal.

The inner side wall of the combustion chamber with the tubes 4 forms a gas-tight wall which separates the combustion chamber from the rst gas flue 8. At the rear end of the combustion space, the tubes 4 are arranged at a larger distance from each other or they are staggered so that the gases from the combustion chamber can enter the gas flue 8 from the rear end thereof.

In the illustrated example there are located in the gas flue 8, first, la steam generating heating surface 10, then, a super-heating surface 11 and adjacent thereto, again a steam generating heating surface 12. A-t the front end of the flue 8, the gases are conducted into the second gas ue 13, separated from the rst one by a partition 44, which, at its` front end, leaves an opening 45 for the passage of the gases. In flue 13 two steam genf 2,988,063 y j e erating heating surfaces 14 and 15 and an Veconoinizer 16 are located. The gases leave the boiler at 17. In FIG. 1, the steam generating heating surfaces in the first gas nue 8 and the economizer heating surface 16 in the second gas flue 13 and also the gas exit are visible.

FIG. 3 shows the super-heater heating surface 11 in the irst gas ue 8 rand the steam generating heating surface 15 in the second gas ilue 13.

InfFIG. 14 both the steam generating heating surfaces 12 and 14 are visible. All these steam generating heating surfaces, located in the lgas flues, are formed of parallel banks of the same kind of tubes.

A tubular bank is illustrated in FIGS. 5 and 6. It consists of a lower distributor 18 4and an upper collector 19 between which the heated tubes 20 and 20 'arerarranged. The distributors v18 of the banks Kextend from a longitudinal main bank-distributor 21. The bank co1- lectors 19 open into the longitudinal main-bank collector 22. If, as in the illustrated embodiment, a steam generating heating surface is arranged in the first ue 8 and an economizei' heating surface 16 in the second flue 13, sideways of the steam generating` heating surface, an extension or connectingpiece 23, as shownin FIG. 1, willbe connected to each lower -bank distributor 18 of a tubular bank of FIGS. 5 and 6 in order to connect the distributor 18 with the main distributor 21. If a superhea'ter 11is arranged -in the rst flue and a steam generating ,heating surface 15 in the second flue, as shown in FIGS. 2 and 3, a connecting or extension piece Y24 will beY connected toY each upper bank collector in order to connect these collectors with the longitudinal main bank collector 22. The extension pieces 24 may simultaneously rserve as supports from which the tubes of the Vsuperheating surface vmay be suspended, vas clearly visible in FIGS. 1 1, 12 and 13.4 Similarly, the tubes of the lecon# 18 and collectors 19' are connected'to each other only by straight tubes 26 centrally inserted into the distributor. 18 and collector 19. This form of production is relatively simple. However, less-heating surface can be provided within a given space if it is required that the collectors 19 are somewhat distanced from each other in order to allow for cleaning or accessibility. In the form accordingto FIGS. 9 and 10, only straight tubes 27 are also used which, however, are eccentrically secured to the vdistributor 18" and collector 19". -From thelongitudinal section of FIG.V 11 through the rst flue 8, it is apparent how the super-heater tubes are suspended from the intermediate pieces 24 which connect the collectors of the tubular elements of the second flue to the longi-` tudinal main bank collector 22, visible in FIGS. '1, 3 and 4..- If the bank collectors 19 are located relatively closely to each other, the intermediate connecting pieces 24 would have to be located also close tov each other and it would be impossible to pass the super-heater tubes between t'wo bank collector tubes. For this reason, it is proposed to connect .the distributors 19 of two or several Y tubular elements in the second flue to one connecting ornizer 16'1nay be supportedand bear on the intermediate pieces 23, as shown in FIGS. 14 and 15. Y

If-stearn generating heating surfaces are arranged side by side in the first and second ilues, as shown in FIG. 4, tw 'sets of tubes 20 and 20" may be connected according to FIGS. 5 and 6, that means, the tubes of the one set may be bent at their lower ends and the tubes of theother set at their upper ends. However, in all instances, the tubular elements used are equal and it is possible to produce such tubular elements according to one drawing, with the same tooling whereby the costs will bes'ubstantially reduced. -By changing the number of the groups of banks in the .gas current in front and in the rear of the super-heater, it is possible to adapt the same structural element to the prevailing conditions of pressure or super-heated steam temperature. It is also possible to operate with the same type of tubular elements within certain output limits. With larger output changes, tubular 'elements with other dimensions as to height or width may be selected.

As Vit will be clear from FIGS. l, 3 and 4, covers 25 are provided to close the space on top ofthe gas ue's 8 and 13. Owing thereto, the convection heating surfaces in the gas nues are readily accessible from the top so that, after the removal ofthe cover, the heating Ysurfaces in the gas ues can be cleaned, if necessary by hand, or repairs of the tubular groups can be performed and the :superheater and economzer heating surfaces can be removed through the tfop.

If the tubular elements are made according to FIGS. 5 and `6, cleaning is facilitated inasmuch as the distributor 19 is located somewhat laterally on account whereof the individual tubes are better accessible from the top. The production of the tubular elements is done in such a manner Athat the tubes are bent inwards on the one end and the straight ends of the tube 20 are inserted into the distributor 18'whereas the straight ends of the tube 20' are inserted into Vthe collector 19.

Modified forms of the banks are illustrated in FIGS. 7 vto 10. Inthe-fonn o-f FIGS. 7 and A8, the'distributors intermediate piece 2li-'vas this is illustrated in FIGS. 12 and 13.

""FIGS. 14 and 1.5 Vshow'how the economizer tubes 16 are supported on the extension kpieces 23 which connect the distributors 18 'to the main Vlongitudinal distributors 21.

In ordertorender the cleaning of the spaces below the heating surfaces ofthe vfirst gas flue 8 possible, a funnellike structure `28 "according to FIG. 1l may be provided under these'heating surfaces. In the second ue 13, funnels are also-arranged (shown in dash lines) which are staggered with lrespectV to the funnels in the gas iiue 8, so that cleaning openings -29`may be passed through the funnel s'a'fddles 46 ofthe gas line 13 without permitting the gases to'pa'ss l'directly'from one flue to the other except througlifthe aforementioned opening 45.

The watercirculation occurs in the boiler according tothe invention in the following manner: Y From the drum 3'1 boiler water flows through the downcomers 32 to the longitudinal distributor 33 on the outer side -wall 5 of the combustion chamber and from there to the `transverse distributors 34fand 34' at the front wall and rear wall, respectively, of the combustion chamber. The transverse distributors are connected bythe longi- Vtudinal distributorr35 at the inner side 4 of the combustion-chamber. The transverse distributors 34 and 34' are extended and connected to the longitudinal distributor 21 of the convection-heating surface and supply the latter with' circulation water. 'Ihe side wall tubes 4 and 5 of the combustion chamber open into a longitudinal collector 36 whichis connected to the drum 31 through front 4and vrear wall collectors 37. In addition, a steam conduit 38 connects the longitudinal collector 36 with the drum 31'.- The collector 22 to which all the tubular elements of the steam generating heating surfaces of the nues 8 and 13 are connected is valso in communication with the drum 31 through the collectors 37' and steam conduits 39. Itis advisable to locate'the collector 22 above the inner side wall 4 of lthe combustion chamber because in that event'the tubes of the heating surface in the gas flue can be placed close to this side wall.

YIn order to increase the water circulation -in the tubular elements of the convection heating surface, collector 22 may be connected by tubes 40 with the vertical return tubes 41 so that aseparate circulation occurs from the collector 22 'back to the distributor 21 and that accordingly ythedrum :can b'e arranged relativelyfar from this heating :surface so that one need not be afraid of a too weak circulation in the convection heating surface.

' VSuitably the kdrum bears on the down pipes 32 and the `distributors 33, 34, 35 and 21 together with the return vpipes l'41 andthe upper collectors 36, 37 Vand 22 will be combined into Ja boiler framework whereby lthe 'entire boiler-can be constructed so as to require relatively very little space.

With a particularly long boiler of this type, it may be advisable to connect the upper ends of the vertical return tubes 41, as in FIG. 16, by a longitudinal tube 42 and to arrange additional return tubes 43 distributed over the entire length of the tube 42 and connecting these tubes with the distributor 21.

In the embodiment according to FIGS. 1 to 4, the partition 44 between the gas ue 8 and the ilue 13 is illustrated as made of stone or other refractory material. This partition can be installed from the spaces between the individual heating surface groups `10, 11, 12, 13, 14, 15, 16. However, it is also possible and advisable, in the higher temperature range, to form this partition between the tirst and second flues of steam generating tubes.

This can be done in such a way that one arranges in lieu of the partition of refractory material, yfin-provided tubes on the bank distributor tubes 18 whereby a gastight closure from one gas -ue to the other will-be formed. Special tubes can be arranged in the spaces between the individual groups of Vheating surfaces.

It will be apparent to those skilled in the art that many alterations and modications of the structure illustrated and described can be made without departure from the essence and spirit of the invention which for that reason shall not be limited but by the scope of the appended claims.

I claim:

l. A steam generator comprising a combustion chamber and at least one gas line on substantially the same bottom level as and laterally of said combustion chamber on the one side thereof and extending substantially the height and the length of said combustion chamber, said steam generator having a front wall with an opening therein for fuel supply to the combustion chamber, a rear wall, an outer side wall opposite said flue, an inner side wall between said combustion chamber and said ue, and an outer ue wall opposite said inner side wall,

openings being provided in the rear end of the inner l side wall and the opposite end of the outer flue wall so as to cause a substantially horizontal current of the combustion gases in the flue parallel to a lengthwise flow of the combustion gases in the combustion chamber;

groups of parallel banks of parallel convection heating tubes in said ue, said banks extending substantially through the entire height of the line and including individual bank distributors and collectors extending transversely of the direction of the gas current in said llue, a steam separator drum lengthwise and on top of the outer side wall of said combustion chamber, and a removable top cover of said steam generator above said ilue, a free space being provided on top of said groups of banks between said bank collectors and said cover.

2. A steam generator comprising a combustion chamber and at least two gas flues on substantially the same bottom level as and laterally of said combustion chamber on the one side thereof and extending substantially the height and the length of said combustion chamber; said steam generator having a front wall with an opening for fuel supply to the combustion chamber, a rear wall, an outer side wall opposite said llues, an inner side wall between said combustion chamber and the first one of said gas flues, a partition between said gas flues and an outer flue wall of said second flue opposite said partition, openings being provided in the rear end portions of said inner wall and said outer ilue wall and in the front end portion of said partition so as to cause a substantially horizontal current of the combustion gases in the ilues parallel to a lengthwise current of the gases in the combustion chamber; groups of parallel banks of parallel convection heating tubes in said dues, said banks extending substantially through the entire height of the .ues and including individual bank distributors and bank collectors extending transversely of the direction of the gas current in said flues; a steam separator 4drum length- Wise and on top of the outer side wall of said combus tion chamber, and a removable top cover of said steam generator above each of said ues, free spaces being provided on top of said groups of banks between said bank collectors and said cover.

3. A steam generator comprising a combustion chamber and at least two gasues on substantially the same bottom level as and laterally of said combustion chamber on the one side'` thereof and extending substantially theheight and -the length'of said combustion chamber; lsaid steam generator having a front wall with an opening for fuel supply to the combustion chamber, a rear wall, an outer side wall opposite said flues, an inner side wall between said combustion, chamber and the first one of said gas ilues, avpartition between said gas ues and an outer uewall of said second flue opposite said partition, openings being provided in the rear end portions vof said inner` wall and said outer ue wall and in the front end portion of said partition so as to cause a substantially horizontal current of the combustion gases in the iiues parallelto aylengthwise current of the gases in the'combustion chamber; groups of parallel banks of parallel convection heating tubes in said ues, said banks extending substantially through the entire height of the llues and including individual bank distributors and bank collectors extending transversely of the direction of the gas current in said lues; a steam separator drum lengthwise and on top of the outer side wall of said combustion chamber, one main bank distributor located at the foot of said outer liue wall and connected to said individual bank distributors in both llues, additional distr'ibutors along the foot ends of the walls of said com- -bustion chamber and kconnected to said main bank distributor, and downcomers at the ends of said drum con'- necting the latter to said additional distributors.

4. A steam generator as in claim 3, further comprising a main bank collector located above said inner side wall and connected to said individual bank collectors, risers lining the combustion chamber on both side walls and being inwardly bent with their upper portions, a common longitudinal collector to which said risers are connected, and connector tubes connecting said main collector and said common collector to said drum.

5. A steam generator as in claim 4 wherein said main bank collector is located within a free space above the inwardly -bent portions of said inner wall risers.

6. A steam generator comprising a combustion chamber and at least two gas ues on substantially the same .bottom level as and laterally of said combustion chamber on the one side thereof and extending substantially 'the height and the length of said combustion chamber;

said steam generator having a front wall with an opening for fuel supply to the combustion chamber, a rear wall, an outer side wall opposite said ilues, an inner side wall between said combustion cham-ber and the first one of said gas ilues, a partition between said gas tlues and an outer ue wall of said second flue opposite said partition, openings being provided in the rear end portions of said inner Wall and said outer llue wall and in the front end portion of said partition so as to cause a substantially horizontal current of the combustion gases in the ilues parallel to a lengthwise current of the gases in the combustion chamber; groups of parallel banks of parallel steam generating tubes, said groups being located in said ilues, respectively, said banks extending substantially through the entire height of the iiues and including individual -bank distributors and bank collectors extending transversely of the direction of the gas current of said ues, a main bank distributor to which said individual bank distributors of both llues are connected, and a main bank collector to which said individual bank collectors of lboth Itiues are connected, said main bank distributor being located at the foot of said outer ue wall,- and said main bankcollector being located on top of. said inner wall, said individual bank vdistributors of said -vrst flue includingtubular connecting pieces extending rthrough said partition and connectingsaid individual bank distributors to said main Vbank distributor, and said 4main collector.

7. A steam generator as in claim 6 wherein each two bank collectors of said second ilue ,have one of said connecting pieces in common.

8. A steam generator as in claim 6, further comprising other heating surfaces such as a Vsuperheater and an economizer, such other heating surfaces being carried by at least some of said Vconnecting pieces.

9. A steam generator as in claim 2 wherein said distributor and collector of each bank of at least one of said groups are formed as headers located in Vertical Y planes, respectively, slightly spaced from each other, the

lbeing connected to one of Vsaid headers, and the bent upper ends` being connected to the other header.

10. A steam generator as in claim 2 wherein the bot-` toms of said ues underneath said groups of banks `are provided with a plurality of funnel-likemdust` collecting dips extending transverse with respect torthe iluesrtheV dips of the one ue being staggered withl vrespect'torthe dips of the other ilue, cleaning passages being provided lin said outer -tlue wall in communication with `said dips,

respectively, said passages of said rst ue extending through the risers of said dips between each two adjacent dips of said second ue. a

11. A steam generator as in claim 3, said partition being formed of steam generating tubes.

References ,Cited in the le of this patent UNITED STATES PATENTS 1,154,910 Doherty Sept. 28, `1915 1,729,259 Jacobus T Sept. 24, 1929 1,930,688 Murray Oct. 17, 1933 2,204,350 Frisch June 11, 1940 2,563,489 Rowand Aug. 7, 1951 FOREIGN PATENTS 762,851 Great Britain Dec. 5, 1956 

